1. Field of the Invention
The present invention relates to a rotary encoder.
2. Description of the Prior Art
Conventional rotary encoders comprise a rotary plate having a plurality of slits defined therein and spaced an equal distance from each other in a direction circumferentially thereof. These slits are selectively sensed by a sensor during rotation of the rotary plate to determine the angle of rotation of the rotary plate in terms of the number of slits detected and also to determine the peripheral velocity of the rotary plate in terms of the number of slits detected for a given length of time.
With conventional rotary encoders however, the detection of the peripheral velocity of the rotary plate is essentially such as to detect the angle of rotation from a position at which rotation of the rotary plate is initiated. The conventional rotary encoder is unable to detect the angle of rotation of the rotary plate from a specific reference angular position during the continued rotation of the rotary plate.